//
// Created by liuzikai on 2019-05-25.
//

/*
    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    shell.c
 * @brief   Revised CLI shell header from ChibiOS Shell.
 *
 * @addtogroup shell_chibios
 * @{
 */

#include <string.h>

#include "ch.h"
#include "hal.h"
#include "shell_base.h"
#include "shell_base_cmd.h"
#include "printf.h"

/*===========================================================================*/
/* Module local definitions.                                                 */
/*===========================================================================*/

/*===========================================================================*/
/* Module exported variables.                                                */
/*===========================================================================*/

/**
 * @brief   Shell termination event source.
 */
event_source_t shell_terminated;

/*===========================================================================*/
/* Module local types.                                                       */
/*===========================================================================*/

/*===========================================================================*/
/* Module local variables.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Module local functions.                                                   */
/*===========================================================================*/

static char *parse_arguments(char *str, char **saveptr) {
    char *p;

    if (str != NULL)
        *saveptr = str;

    p = *saveptr;
    if (!p) {
        return NULL;
    }

    /* Skipping white space.*/
    p += strspn(p, " \t");

    if (*p == '"') {
        /* If an argument starts with a double quote then its delimiter is another
           quote.*/
        p++;
        *saveptr = strpbrk(p, "\"");
    } else {
        /* The delimiter is white space.*/
        *saveptr = strpbrk(p, " \t");
    }

    /* Replacing the delimiter with a zero.*/
    if (*saveptr != NULL) {
        *(*saveptr)++ = '\0';
    }

    return *p != '\0' ? p : NULL;
}

static void list_commands(BaseSequentialStream *chp, const ShellCommand *scp) {

    while (scp->sc_name != NULL) {
        chprintf(chp, "%s ", scp->sc_name);
        scp++;
    }
}

static bool cmdexec(ShellConfig *scfg, const ShellCommand *scp, BaseSequentialStream *chp,
                    char *name, int argc, char *argv[]) {
    //for debug
    // chprintf(chp,"argc:%d" SHELL_NEWLINE_STR,argc);
    // the argc here exclude the command itself i.e. command a b c, the number of args is 3
    while (scp->sc_name != NULL) {// current shell command in the given command list is not null
        if (strcmp(scp->sc_name, name) == 0) {//  and match the input command name
            bool ret;
            if (!scp->sc_arg) {// if the predefined args exists in the ShellCommand struct, then use the default one(default sc_channel(SerialDriver) defined in Shell::start in shell.cpp)
                // no predefined args, then use the input args
                ret = scp->sc_function(chp, argc, argv); // in each callback function, if it is executed correctly then return true
            } else {
                //TODO Here we just pass void* as BaseSequentialStream *, maybe fix this someday
                // It means if we want to pass other type of pointer(like 'this' pointer in a class),
                // we still need to convert the type to (BaseSequentialStream *),
                // since it is hard coded in marco DEF_SHELL_CMD_START in shell.h
                ret = scp->sc_function(scp->sc_arg, argc, argv);
            }
            if (!ret) {// args error, print hints
                if (scp->sc_arguments) {
                    chMtxLock(scfg->sc_mutex);
                    {
                        chprintf(chp, "Usage: %s %s" SHELL_NEWLINE_STR, scp->sc_name, scp->sc_arguments);
                    }
                    chMtxUnlock(scfg->sc_mutex);
                } else {
                    chMtxLock(scfg->sc_mutex);
                    {
                        chprintf(chp, "Usage: %s?" SHELL_NEWLINE_STR, scp->sc_name);
                    }
                    chMtxUnlock(scfg->sc_mutex);
                }
            }
            return false;
        }
        scp++;
    }
    // if error return true
    return true;
}

#if (SHELL_USE_HISTORY == TRUE) || defined(__DOXYGEN__)

static void del_histbuff_entry(ShellHistory *shp) {
    int pos = shp->sh_beg + *(shp->sh_buffer + shp->sh_beg) + 1;

    if (pos >= shp->sh_size)
        pos -= shp->sh_size;

    shp->sh_beg = pos;
}

static bool is_histbuff_space(ShellHistory *shp, int length) {

    if (shp->sh_end >= shp->sh_beg) {
        if (length < (shp->sh_size - (shp->sh_end - shp->sh_beg + 1)))
            return true;
    } else {
        if (length < (shp->sh_beg - shp->sh_end - 1))
            return true;
    }

    return false;
}

static void save_history(ShellHistory *shp, char *line, int length) {

    if (shp == NULL)
        return;

    if (length > shp->sh_size - 2)
        return;

    while ((*(line + length - 1) == ' ') && (length > 0))
        length--;

    if (length <= 0)
        return;

    while (!is_histbuff_space(shp, length))
        del_histbuff_entry(shp);

    if (length < shp->sh_size - shp->sh_end - 1)
        memcpy(shp->sh_buffer + shp->sh_end + 1, line, length);
    else {
        /*
         * Since there isn't enough room left at the end of the buffer,
         * split the line to save up to the end of the buffer and then
         * wrap back to the beginning of the buffer.
         */
        int part_len = shp->sh_size - shp->sh_end - 1;
        memcpy(shp->sh_buffer + shp->sh_end + 1, line, part_len);
        memcpy(shp->sh_buffer, line + part_len, length - part_len);
    }

    /* Save the length of the current line and move the buffer end pointer */
    *(shp->sh_buffer + shp->sh_end) = (char) length;
    shp->sh_end += length + 1;
    if (shp->sh_end >= shp->sh_size)
        shp->sh_end -= shp->sh_size;
    *(shp->sh_buffer + shp->sh_end) = 0;
    shp->sh_cur = 0;
}

static int get_history(ShellHistory *shp, char *line, int dir) {
    int count = 0;

    if (shp == NULL)
        return -1;

    /* Count the number of lines saved in the buffer */
    int idx = shp->sh_beg;
    while (idx != shp->sh_end) {
        idx += *(shp->sh_buffer + idx) + 1;
        if (idx >= shp->sh_size)
            idx -= shp->sh_size;
        count++;
    }

    if (dir == SHELL_HIST_DIR_FW) {
        if (shp->sh_cur > 0)
            shp->sh_cur -= 2;
        else
            return 0;
    }

    if (count >= shp->sh_cur) {
        idx = shp->sh_beg;
        int i = 0;
        while (idx != shp->sh_end && shp->sh_cur != (count - i - 1)) {
            idx += *(shp->sh_buffer + idx) + 1;
            if (idx >= shp->sh_size)
                idx -= shp->sh_size;
            i++;
        }

        int length = *(shp->sh_buffer + idx);

        if (length > 0) {
            shp->sh_cur++;

            memset(line, 0, SHELL_MAX_LINE_LENGTH);
            if ((idx + length) < shp->sh_size) {
                memcpy(line, (shp->sh_buffer + idx + 1), length);
            } else {
                /*
                 * Since the saved line was split at the end of the buffer,
                 * get the line in two parts.
                 */
                int part_len = shp->sh_size - idx - 1;
                memcpy(line, shp->sh_buffer + idx + 1, part_len);
                memcpy(line + part_len, shp->sh_buffer, length - part_len);
            }
            return length;
        } else if (dir == SHELL_HIST_DIR_FW) {
            shp->sh_cur++;
            return 0;
        }
    }
    return -1;
}

#endif

#if (SHELL_USE_COMPLETION == TRUE) || defined(__DOXYGEN__)

static void get_completions(ShellConfig *scfg, char *line) {
    const ShellCommand *lcp = shell_local_commands;
    const ShellCommand *scp = scfg->sc_commands;
    char **scmp = scfg->sc_completion;
    char help_cmp[] = "help";

    if (strstr(help_cmp, line) == help_cmp) {
        *scmp++ = help_cmp;
    }
    while (lcp->sc_name != NULL) {
        if (strstr(lcp->sc_name, line) == lcp->sc_name) {
            *scmp++ = (char *) lcp->sc_name;
        }
        lcp++;
    }
    if (scp != NULL) {
        while (scp->sc_name != NULL) {
            if (strstr(scp->sc_name, line) == scp->sc_name) {
                *scmp++ = (char *) scp->sc_name;
            }
            scp++;
        }
    }

    *scmp = NULL;
}

static int process_completions(ShellConfig *scfg, char *line, int length, unsigned size) {
    char **scmp = scfg->sc_completion;
    char **cmp = scmp + 1;
    char *c = line + length;
    int clen = 0;

    if (*scmp != NULL) {
        if (*cmp == NULL) {
            clen = strlen(*scmp);
            int i = length;
            while ((c < line + clen) && (c < line + size - 1))
                *c++ = *(*scmp + i++);
            if (c < line + size - 1) {
                *c = ' ';
                clen++;
            }
        } else {
            while (*(*scmp + clen) != 0) {
                while ((*(*scmp + clen) == *(*cmp + clen)) &&
                       (*(*cmp + clen) != 0) && (*cmp != NULL)) {
                    cmp++;
                }
                if (*cmp == NULL) {
                    if ((c < line + size - 1) && (clen >= length))
                        *c++ = *(*scmp + clen);
                    cmp = scmp + 1;
                    clen++;
                } else {
                    break;
                }
            }
        }

        *(line + clen) = 0;
    }

    return clen;
}

static void write_completions(ShellConfig *scfg, char *line, int pos) {
    BaseSequentialStream *chp = scfg->sc_channel;
    char **scmp = scfg->sc_completion;

    if (*(scmp + 1) != NULL) {
        chprintf(chp, SHELL_NEWLINE_STR);
        while (*scmp != NULL)
            chprintf(chp, " %s", *scmp++);
        chprintf(chp, SHELL_NEWLINE_STR);

        chprintf(chp, SHELL_PROMPT_STR);
        chprintf(chp, "%s", line);
    } else {
        chprintf(chp, "%s", line + pos);
    }
}

#endif

/*===========================================================================*/
/* Module exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Shell thread function.
 *
 * @param[in] p         pointer to a @p BaseSequentialStream object
 */
THD_FUNCTION(shellThread, p) {
    int n;
    ShellConfig *scfg = p;
    BaseSequentialStream *chp = scfg->sc_channel;
    const ShellCommand *scp = scfg->sc_commands;
    char *lp, *cmd, *tokp, line[SHELL_MAX_LINE_LENGTH];
    char *args[SHELL_MAX_ARGUMENTS + 1];

#if SHELL_USE_HISTORY == TRUE
    *(scfg->sc_histbuf) = 0;
    ShellHistory hist = {
            scfg->sc_histbuf,
            scfg->sc_histsize,
            0,
            0,
            0
    };
    ShellHistory *shp = &hist;
#else
    ShellHistory *shp = NULL;
#endif

    chprintf(chp, SHELL_NEWLINE_STR);
    chprintf(chp, SHELL_WELCOME_STR SHELL_NEWLINE_STR);
#if SHELL_NO_ECHO_MODE == TRUE
    chprintf(chp, "NOTICE: IN NO ECHO MODE NOW. YOU WON'T GET ECHO FOR INPUT COMMANDS." SHELL_NEWLINE_STR);
#endif
    while (true) {
        chprintf(chp, SHELL_PROMPT_STR);
        // out variable: line
        // true then sleep for 100ms
        if (shellGetLine(scfg, line, sizeof(line), shp)) {
#if (SHELL_CMD_EXIT_ENABLED == TRUE) && !defined(_CHIBIOS_NIL_)
            chprintf(chp, SHELL_NEWLINE_STR);
      chprintf(chp, "logout");
      break;
#else
            /* Putting a delay in order to avoid an endless loop trying to read
               an unavailable stream.*/
            osalThreadSleepMilliseconds(100);
#endif
        }
        lp = parse_arguments(line, &tokp);
        cmd = lp;
        n = 0;
        // parse args
        while ((lp = parse_arguments(NULL, &tokp)) != NULL) {
            if (n >= SHELL_MAX_ARGUMENTS) {
                chprintf(chp, "too many arguments" SHELL_NEWLINE_STR);
                cmd = NULL;
                break;
            }
            args[n++] = lp;
        }
        args[n] = NULL;
        //analyze command
        if (cmd != NULL) {
            if (strcmp(cmd, "help") == 0) {
                if (n > 0) {
                    chprintf(chp, "Usage: help" SHELL_NEWLINE_STR);
                    continue;
                }
                chprintf(chp, "Commands: help ");
                list_commands(chp, shell_local_commands);
                if (scp != NULL)
                    list_commands(chp, scp);
                chprintf(chp, SHELL_NEWLINE_STR);
            } else if (cmdexec(scfg, shell_local_commands, chp, cmd, n, args) &&
                       ((scp == NULL) || cmdexec(scfg, scp, chp, cmd, n, args))) {
                // error command
                chprintf(chp, "%s", cmd);
                chprintf(chp, " ?" SHELL_NEWLINE_STR);
            }
        }
    }
    shellExit(MSG_OK);
}

/**
 * @brief   Shell manager initialization.
 *
 * @api
 */
void shellInit(void) {

    chEvtObjectInit(&shell_terminated);
}

#if !defined(_CHIBIOS_NIL_) || defined(__DOXYGEN__)

/**
 * @brief   Terminates the shell.
 * @note    Must be invoked from the command handlers.
 * @note    Does not return.
 *
 * @param[in] msg       shell exit code
 *
 * @api
 */
void shellExit(msg_t msg) {

    /* Atomically broadcasting the event source and terminating the thread,
       there is not a chSysUnlock() because the thread terminates upon return.*/
    chSysLock();
    chEvtBroadcastI(&shell_terminated);
    chThdExitS(msg);
}

#endif

/**
 * @brief   Reads a whole line from the input channel.
 * @note    Input chars are echoed on the same stream object with the
 *          following exceptions:
 *          - DEL and BS are echoed as BS-SPACE-BS.
 *          - CR is echoed as CR-LF.
 *          - 0x4 is echoed as "^D".
 *          - Other values below 0x20 are not echoed.
 *          .
 *
 * @param[in] scfg      pointer to a @p ShellConfig object
 * @param[in] line      pointer to the line buffer
 * @param[in] size      buffer maximum length
 * @param[in] shp       pointer to a @p ShellHistory object or NULL
 * @return              The operation status.
 * @retval true         the channel was reset or CTRL-D pressed.
 * @retval false        operation successful.
 *
 * @api
 */
bool shellGetLine(ShellConfig *scfg, char *line, unsigned size, ShellHistory *shp) {
    char *p = line;
    BaseSequentialStream *chp = scfg->sc_channel;
#if SHELL_USE_ESC_SEQ == TRUE
    bool escape = false;
  bool bracket = false;
#endif

#if SHELL_USE_HISTORY != TRUE
    (void) shp;
#endif

    while (true) {
        char c;

        if (streamRead(chp, (uint8_t *) &c, 1) == 0)
            return true;
#if SHELL_USE_ESC_SEQ == TRUE
        if (c == 27) {
      escape = true;
      continue;
    }
    if (escape) {
      escape = false;
      if (c == '[') {
        escape = true;
        bracket = true;
        continue;
      }
      if (bracket) {
        bracket = false;
#if SHELL_USE_HISTORY == TRUE
        if (c == 'A') {
          int len = get_history(shp, line, SHELL_HIST_DIR_BK);

          if (len > 0) {
            _shell_reset_cur(chp);
            _shell_clr_line(chp);
            chprintf(chp, "%s", line);
            p = line + len;
          }
          continue;
        }
        if (c == 'B') {
          int len = get_history(shp, line, SHELL_HIST_DIR_FW);

          if (len == 0)
            *line = 0;

          if (len >= 0) {
            _shell_reset_cur(chp);
            _shell_clr_line(chp);
            chprintf(chp, "%s", line);
            p = line + len;
          }
          continue;
        }
#endif
      }
      continue;
    }
#endif
#if (SHELL_CMD_EXIT_ENABLED == TRUE) && !defined(_CHIBIOS_NIL_)
        if (c == 4) {
      chprintf(chp, "^D");
      return true;
    }
#endif
        if ((c == 8) || (c == 127)) {
            if (p != line) {
#if SHELL_NO_ECHO_MODE == FALSE
                streamPut(chp, 0x08);
                streamPut(chp, 0x20);
                streamPut(chp, 0x08);
#endif
                p--;
            }
            continue;
        }
        if (c == '\r') {
#if SHELL_NO_ECHO_MODE == FALSE
            chprintf(chp, SHELL_NEWLINE_STR);
#endif
#if SHELL_USE_HISTORY == TRUE
            save_history(shp, line, p - line);
#endif
            *p = 0;
            return false;
        }
#if SHELL_USE_COMPLETION == TRUE
        if (c == '\t') {
            if (p < line + size - 1) {
                *p = 0;

                get_completions(scfg, line);
                int len = process_completions(scfg, line, p - line, size);
                if (len > 0) {
                    write_completions(scfg, line, p - line);
                    p = line + len;
                }
            }
            continue;
        }
#endif
#if SHELL_USE_HISTORY == TRUE
        if (c == 27) {
            /* Look for ^[B and ^[A */
            if (streamRead(chp, (uint8_t *) &c, 1) == 0)
                return true;
            if (c != '[')
                return true;
            if (streamRead(chp, (uint8_t *) &c, 1) == 0)
                return true;
            if (c == 'B') {
                int len = get_history(shp, line, SHELL_HIST_DIR_FW);

                if (len == 0)
                    *line = 0;

                if (len >= 0) {
                    _shell_reset_cur(chp);
                    _shell_clr_line(chp);
                    chprintf(chp, "%s", line);
                    p = line + len;
                }
                continue;
            } else if (c == 'A') {
                int len = get_history(shp, line, SHELL_HIST_DIR_BK);

                if (len > 0) {
                    _shell_reset_cur(chp);
                    _shell_clr_line(chp);
                    chprintf(chp, "%s", line);
                    p = line + len;
                }
                continue;
            } else {
                continue;
            }
        }

#endif
        if (c < 0x20) {
            continue;
        }
        if (p < line + size - 1) {
#if SHELL_NO_ECHO_MODE == FALSE
            streamPut(chp, c);
#endif
            *p++ = (char) c;
        }
    }
}

/** @} */
